Growth hormone (GH) secretion is blunted in diabetic rats. In the present experiment we observed that pituitary GH concentrations and the plasma GH response to an exogenous dose of growth hormone-releasing hormone (GHRH) is decreased in streptozotocin-induced diabetic rats (p < 0.02) with respect to normal rats. In an attempt to determine if increased somatostatin (SRIF) secretion is responsible for the decreased GH secretion, we studied the effect of modulating SRIF tone on the GH response to GHRH in normal and streptozotocin-induced diabetic rats. Rats were pretreated with either normal sheep serum and saline (NSS + SAL), somatostatin antibodies (SRIF-Ab), or pyridostigmine (PD), an acetylcholinesterase inhibitor hypothesized to reduce hypothalamic SRIF secretion. Pretreatment of normal rats with SRIF-Ab or PD resulted in an increased GH response to exogenous GHRH in comparison to NSS + SAL-pretreated normal rats at 5 min postinjection. In contrast, pretreatment of diabetic rats with SRIF-Ab or PD did not alter the GH response to exogenous GHRH when compared to NSS + SAL-pretreated diabetic animals. These results suggest that the blunted GH response to exogenous GHRH observed in streptozotocin-induced diabetic rats may not be due to an increase of endogenous SRIF tone.

Clinically, glucocorticoids are important immunosuppressive hormones. Yet, these steroids are also potent inhibitors of growth. We hypothesized that glucocorticoids may partially inhibit growth by increased somatostatin (SRIF) secretion. We tested this hypothesis using passive immunization techniques. Male rats (approximately 50 g) were treated daily (ip) for 33 days with saline (SAL) or dexamethasone (DEX, 40 micrograms/kg) and every fourth day with normal sheep serum (NSS) or SRIF antiserum (SRIF-ab, 0.25 ml). Body wts were recorded daily. Groups (n = 6) were: 1) SAL + NSS, 2) SAL + SRIF-ab, 3) DEX + NSS, and 4) DEX + SRIF-ab. Regression analysis of the growth curves clearly demonstrated differences in body wt gain for the four treatment groups (P less than 0.01). Final body wt of SAL + NSS treated rats was 285 +/- 5 g and 285 +/- 12 g in SAL + SRIF-ab treated rats. DEX + NSS treated rats weighed significantly less (227 +/- 4 g, P less than 0.01) than SAL-treated rats. This glucocorticoid-induced decrease in body wt was partially reversed by the concomitant treatment of rats with SRIF-ab (241 +/- 6 g, P less than 0.05). This observation leads to the conclusion that the inhibitory effect of glucocorticoids on growth may be mediated, in part, by increased SRIF secretion.

Circulatory leukocytes vary significantly in response to acute bouts of exercise. However, little is known concerning the adaptability of this response to chronic intense exercise training. We investigated the circulating leukocytic response to acute exercise in trained athletes during a 28-day intense exercise training program. On day 0, 14, 28 and two days after cessation of the increased training, eight trained male athletes (VO2max greater than 60 ml.kg-1.min-1) were subjected to a 20-km bicycle ergometer time trial. Blood samples were drawn before (PRE, for resting baseline values) and five minutes after (POST, response to acute exercise) the time trial. Beginning on day 0, athletes were instructed to increase the duration of their training 50%. The intense exercise training, which lasted 28 days, was verified weekly. Acute bouts of exercise caused a significant increase (p less than 0.05) in circulating white blood cells, lymphocytes, polymorphonuclear neutrophils and monocytes. The baseline resting values and the magnitude of the response to the acute bouts of exercise in the above parameters were not different during the 28 days of chronic intense exercise training or 2 days after cessation of training as compared to the values observed on day 0. Similarly there was a significant increase (p less than 0.05) in cortisol levels in response to the acute bouts of exercise during the chronic intense exercise training, but the increases were not different from that observed under baseline conditions. These results lead to the conclusion that chronic intense exercise training does not alter the circulating leukocytic response to acute exercise.

Fatal septicemia developed in a splenectomized patient with hairy cell leukemia following a dog bite. Capnocytophaga canimorsus, a slowly growing gram-negative bacillus, was isolated from the patient's blood. Although a rare complication of dog bites in the normal population, this bacterium should be suspected and promptly treated in immunologically compromised dog bite victims. Furthermore, immunocompromised patients should be made aware of the dangers of dog ownership.

A total of 120 Vibrio species were isolated from 588 patients with acute diarrheal disease during an outbreak of gastrointestinal tract infections at different locations in the lower Cross River Basin of Nigeria. Vibrio cholerae 01, biotype El Tor, serotype Ogawa, was the prominent organism isolated from the Vibrio-associated diarrheal cases. During the 3 months of study, V. cholerae non-Ol was recovered from 10 patients while Vbrio parahaemolyticus was recovered from 19 patients. The significance of this study is the recognition that there is an ecological niche which supports V. cholerae non-Ol and V. parahaemolyticus in the Cross River Basin of Nigeria.