No abstract

Objective: To investigate the kinetics of insulin-like growth factor-1 receptor (IGF-1R) expression in PHA-stimulated T lymphocytes. Methods: IGF-1R protein and mRNA were detected by flow cytometry and RT-PCR respectively, between 0 and 48 h after cell activation. Results: Few minutes after T lymphocytes were activated, internalization of the IGF-1R from the cell membrane was observed, achieving the lower level between 1 and 6 h and was accompanied by a reduction in its mRNA. This was followed by re-expression of IGF-1R on the cell surface and an increase in IGF-1R mRNA levels in the cytoplasm, reaching levels higher than those recorded initially after 48 h activation. Conclusion: This down- and up-regulation suggests that restoration of IGF-1R would be the result of receptor recycling and de novo synthesis and highlights its importance for T lymphocyte proliferation.

No abstract

Pancreatectomized diabetic dogs, deprived of insulin treatment and anesthetized, were infused intravenously for one hour with a fatty emulsion (Lipomul) and kept under observation for six hours. During this period there was a significant decrease in ketonemia and prolonged persistence of hyperlipemia when compared with normal dogs similarly infused. DIABETES 14:33-35, January 1965.In a previous paper 1 the influence of hormonal factors on diabetic ketosis of pancreatectomized dogs was studied. In most of the cases hyperlipemia appeared before ketonemia. There were, however, certain exceptions; the most remarkable one was seen in pancreatectomized-hypophysectomized dogs, in which the injection of cortisol provoked marked hyperlipemia, but was not followed by an increase in ketonemia. This fact led us to study the effects of hormones on pancreatectomized dogs in which lipids were injected intravenously. MATERIAL AND METHODSTwenty-five dogs were used; fourteen were subjected to total pancreatectomy and eleven served as controls. The experiments were performed five to seven days after the operation and approximately sixteen hours after the last meal. The dogs weighed 4 to 18 kg., and were anesthetized with sodium pentobarbital (33 mg. per kg. of body weight).The pancreatectomized dogs were fed with 40 gm. per kg. of raw heart beef and 70 gm. of raw pancreas daily.The animals were divided into four groups as follows: (I) normal dogs; (II) normal dogs infused with Lipomul* for one hour; (III) totally pancreatecto-

Forty non-lactating, cyclic adult Pelibuey ewes were randomly divided into six groups. Estrus was synchronized within each group using intravaginal sponges and prostaglandin F2α injection at the time of the sponge removal. The sponges were inserted and removed on different dates in each group, but all the groups except the control one were first exposed to rams on the same date (July 17 th ), so that at the time of the first exposure the ewes were either on day 0 (group D0; n = 7), 3 (group D3; n = 7), 8 (group D8; n = 7), 12 (group D12; n = 7) or 14 (group D14; n = 7) of their synchronized estrous cycle. Thereafter the ewes of these groups remained continuously exposed to the males until all the females showed estrus. The ewes in the control group (CG; n = 5) remained isolated from all the males, except for 5-minute periods at the time of estrus detection, which was carried out three times a day. Progesterone concentrations were determined in plasma samples taken daily from two days before the initial exposure to the males until the onset of the next estrus. There were no differences in estrous cycle length between the groups exposed to rams and the control group (P > 0.05). The interval from the assumed onset of the estrous cycle (48 h after sponge removal) until the occurrence of luteolysis was not different between the control group and any of the groups exposed to the males. The interval from luteolysis to estrus was not modified by exposure to the males (P > 0.05). Estrus duration was shorter (P < 0.06) in the control group than in group D3. It is concluded that the exposure of cyclic Pelibuey ewes to males does not advance the time of luteolysis and does not affect the length of the estrous cycle. Therefore, the male effect does not synchronize the next estrus of cyclic Pelibuey ewes.