The antipyrine, tritiated water, and N-acetyl-4-aminoantipyrine spaces were determined simultaneously in goats which had been deprived of feed and water for 48 hr. The animals were then killed, minced, and analysed for water, fat, protein, and ash contents. The compositions of the whole and empty bodies of the goats were calculated, and the relationships between the bodily components were compared with those reported for cattle, sheep, and some monogastric species. The relationships found between the components of the whole bodies compared favourably with those derived from the empty bodies. The relationships of the spaces determined in vivo to total body water, fat, and protein were found, and confidence statements were placed on predicted estimates.

Two methods for predicting the body composition of living goats from the tritiated water spaces derived in them were proposed previously from results obtained with 11 goats. The relation of tritiated water spaces to body composition has been studied in an addltlonal 10 goats and 9 sheep, and these results together with those previousl y published have yielded a more precise method for calculating the body composition of living ruminants in terms of water, fat, protein, and ash.

The growth of the first hair coat in male mice was studied during administration of epidermal growth factor (EGF). Injections of 1 or 4 micrograms EGF/g body weight for 14 consecutive days from birth resulted in the development of curved overhairs (monotrichs), caused a retardation in rate of growth in length of hair and a reduction in hair diameter and length of follicle bulb. Growth rate partially recovered after cessation of EGF treatment. However, some of the effects produced by injections of EGF during the formation of the first coat were detected in the second and third generations of hair. Since EGF also retarded rate of body growth, we compared the effect of EGF on hair growth with that of restricting food intake in neonatal mice during the development of the first coat. Hair growth was slowed in underfed animals but the effects were less marked than those found in EGF-treated mice of similar body weights.

Twenty-four adult Merino wethers were given mouse epidermal growth factor (mEGF) subcutaneously at doses ranging from 0.02 to 0.12 mg/kg body weight or intravenously in the dose range 0.10 to 0.14 mg/kg body weight for periods ranging from 3 to 48 h. Plasma concentrations of mEGF were measured by radioimmunoassay and effects of treatment on food consumption and wool growth were observed. Plasma concentrations of the protein sustained for 15-24 h at about 20 ng mEGF/ml (or exceeding this) almost invariably caused feed rejection and casting of the fleeces. This last result clearly indicated disruption of proliferative activity among the replicating cells in wool follicles which regulate wool growth. The inhibitory effects on appetite and wool growth of smaller doses of the protein and of plasma concentrations equal to those above which were sustained for shorter periods have also been examined. Approximately 10% of the dose of mEGF appeared in the urine of three sheep 1 to 3 days after the start of s.c. infusions of 5 mg for 7 h.

Plasma cortisol concentrations and entry rates increased greatly when nine shorn sheep were exposed to cold, wet conditions for periods up to 70 hr.The average entry rate in four of the cold-stressed animals before their rectal temperatures began to fall was 25 \g=m\g./min.,approximately three to four times greater than in the same sheep before exposure (7\ m=. \ 7\g=m\g./min.). The metabolic clearance rates at this time remained unchanged. Plasma cortisol concentration began to increase about 2-3 hr. before the sheeps' rectal temperatures began to fall. The increase continued until concentrations of 100-200 \g=m\g./1. were reached after the sheeps' rectal temperature had fallen. Cortisol entry increased at this time to what may probably be maximal or near maximal rates in the sheep (about 150-200 \g=m\g./min.). Lowered clearance did not appear to contribute substantially to increased plasma cortisol concentrations at rectal temperatures above 34\s=deg\.Since clearance rates did not begin to fall rapidly until rectal temperature fell below about 34\ s=deg\ , cortisol entry during the terminal phase of hypothermia, approximately 76 \g=m\g./min., was very much less than the observed maximum and the high plasma cortisol concentrations measured during this period were residual and sustained by lowered clearance rates.The adrenal cortices and livers of the sheep after severe hypothermia were heavily infiltrated with fat.The effects of shearing alone, studied in a separate experiment, had a transitory effect since plasma cortisol concentrations and entry rates had returned to near their pre-shearing levels by about 27 hr.

The structure of the epidermis and hair-follicle bulbs and the proliferative activities of their component cells were studied in the midside skin of male mice treated with epidermal growth factor (EGF) or saline during formation of the first coat (days 0-21). The epidermis was thickest at birth, but in control animals became progressively thinner as cell size and the number of layers of granular and cornified cells were reduced. EGF treatment from birth resulted in a thickening of the epidermis at 5 days of age, and at 5 and 8 days the histological appearance was strikingly similar to that on the day of birth. At 12 and 21 days the structure of the epidermis of EGF-treated mice more closely resembled that of contemporaneous controls. The mitotic and labeling indices of the basal cells of control epidermis declined throughout the sampling period from peak values on the day of birth. By contrast, these indices were maintained at birth levels in EGF-treated mice for 8 days before declining to approximate those of controls at 12 and 21 days.Hair growth rate was inhibited and hair diameter reduced in EGF-treated mice (Moore et al., 1981a). These observations were reflected in changes in the follicle bulb. Both the growth of the bulb and the increase in numbers of bulb cells observed during the early part of the anagen phase were inhibited by EGF. However, neither the size of the dermal papilla nor the numbers of papilla cells were significantly altered in treated animals. The mitotic index of the bulb cell population declined during the sampling period in both experimental and control groups. However, the labeling index of bulb cells of EGF-treated mice was significantly increased over contemporaneous control values on days 8 and 12. Rather than stimulating epidermal growth during the early postnatal period, these observations indicate that EGF delays the normal process of skin development by maintaining the proliferative and differentiation processes active in the cell populations at the time of birth. As a consequence of this, follicle development and hair growth are inhibited. Levi-Montalcini and Cohen (1960) and Cohen and Elliott (1963) reported that a submaxillary gland protein, epidermal growth factor (EGF), promoted the keratinization of cells of the epidermis when administered to mice after birth, but inhibited hair growth. The apparent discrepancy between the responses of the cells of the epidermis on one hand and those of the epidermal derivatives, the hair follicles, on the other, has not been studied in any detail. Recently, we examined one aspect of this in a study of the monotrichs of the first hair coat in mice. Daily injections of EGF from birth resulted in the development of curved fibers and caused a retardation of length growth rate and a reduction in hair diameter (Moore et al., 1981a). In this report we have compared the morphology and proliferative activities of cell populations of the epidermis and hair-follicle bulbs in EGF-treated and control mice during the growth of the hair coat, wh...

Intravenous infusion of 4.5-4.7 mg of mouse epidermal growth factor (mEGF) into nine castrated male Merino sheep for 26 h resulted in complete casting of the fleeces 6-8 days later. The morphological changes which occurred in the skin were studied in skin samples taken before infusion and at intervals between 1 h and 42 days after the infusion had begun. Wool fibres from the shed fleeces were examined with the scanning electron microscope. Increased cell proliferation occurred in the epidermis and sebaceous glands, whereas the wool follicles regressed. Transient dermal haemorrhages occurred during the first 3 h of infusion. The fibre and inner root sheath in the keratogenous zone of 30-40% of the follicles were partially disrupted within the first 6 h of mEGF infusion; catagen began in all follicle bulbs within 24 h. Fibre and inner root sheath production, although markedly reduced, continued in about 60% of follicles which had partially regressed, but production ceased in the remainder in which tapered ends formed on the fibres prior to shedding. Follicles began to regenerate asynchronously 4-8 days after the beginning of infusion and completed their development during the next 3 weeks. The follicle regression and fleece casting induced by mEGF infusion, and subsequent follicle regeneration were completed more rapidly than observed previously with other depilatory agents, and, except for prolonged epidermal thickening, there was no lasting cutaneous abnormality.

Ten Border Leicester x Merino ewes were divided into two groups on the basis of a initial calculation of their body composition. Group 1 comprised a group of six moderately fat ewes (fat content < 25% body weight), and group 2 four very fat ewes (fat content >40% body weight). The ewes were undernourished by feeding progressively diminishing quantities of a mixture of lucerne chaff and oats (1:1) until group 1 had lost 38.7 and group 2 33.7% of their initial weight in 150–200 days. Feed intakes and wool growth of the sheep were recorded and calculations were made of the body composition in terms of total body water, fat, protein, and ash as undernutrition progressed. Thiocyanate spaces, haematocrit values, and plasma, blood, and red cell volumes were also measured. Generally the ewes in group 1 exhibited a starvation syndrome which was characterized by the gradual depletion of the fat and protein reserves of the body until fat reserves had been almost completely used. Thiocyanate spaces in these ewes expanded relative to body weight, and the circulatory parameters showed a progressive shrinkage of the red cell volume while plasma volume was maintained. The ewes in group 2 differed markedly in their reaction to undernutrition in that three out of the four passed, after a time, into a phase of inappetence and died while still in a very fat condition.