scholarly journals Pituitary-Testicular Responses of Estradiol-17β-Implanted Bull Calves to Continuous versus Pulsatile Infusion of Luteinizing Hormone Releasing Hormone1

1984 ◽  
Vol 58 (4) ◽  
pp. 943-948 ◽  
Author(s):  
Bruce D. Schanbacher
Keyword(s):  
Luteinizing Hormone ◽  
Bull Calves ◽  
Pulsatile Infusion ◽  
Estradiol 17Β

PLASMA CONCENTRATIONS OF LUTEINIZING HORMONE, TESTOSTERONE AND ANDROSTENEDIONE IN CASTRATED AND ADRENALECTOMIZED BULL CALVES

1978 ◽  
Vol 79 (1) ◽  
pp. 137-138 ◽  
Author(s):  
J. J. BASS ◽  
A. J. PETERSON ◽  
E. PAYNE
Keyword(s):  
New Zealand ◽  
Plasma Concentration ◽  
Luteinizing Hormone ◽  
Agricultural Research ◽  
Plasma Concentrations ◽  
Young Male ◽  
Research Centre ◽  
Similar Magnitude ◽  
Research Division ◽  
Bull Calves

Ministry of Agriculture and Fisheries, Research Division, Ruakura Agricultural Research Centre, Hamilton, New Zealand (Received 17 April 1978) An increase in the plasma concentration of luteinizing hormone (LH) occurs in response to castration in bull calves aged 1–4 months; this response is of similar magnitude to that seen in cattle castrated as adults (Odell, Hescox & Kiddy, 1970). In bull calves castrated at birth, however, there is no increase in the plasma concentration of LH until after 28 days of age (Bass, Peterson, Payne & Jarnet, 1977). In other species a range of responses to castration has been reported. Gonadectomy of male guinea-pigs 0–35 days after birth produces an increase in the plasma concentration of LH similar to that observed in guineapigs castrated as adults (Donovan, ter Haar, Lockhart, MacKinnon, Mattock & Peddie, 1975). In contrast, the castration of young male macaques does not cause an immediate increase in the

POSTWEANING PLASMA CONCENTRATIONS OF LUTEINIZING HORMONE AND ESTROGENS IN SOWS: EFFECT OF TREATMENT WITH PREGNANT MARE’S SERUM GONADOTROPIN OR ESTRADIOL-17β PLUS PROGESTERONE

1979 ◽  
Vol 59 (1) ◽  
pp. 159-166 ◽  
Author(s):  
G. W. DYCK ◽  
W. M. PALMER ◽  
S. SIMARAKS
Keyword(s):  
Luteinizing Hormone ◽  
Plasma Concentrations ◽  
Treated Group ◽  
Linear Increase ◽  
Control Group ◽  
History Of ◽  
Serum Gonadotropin ◽  
Effect Of Treatment ◽  
Secretory Pattern ◽  
Estradiol 17Β

The plasma concentrations of luteinizing hormone (LH) and estrogens (E) were determined for 12 sows, from a herd with a history of postweaning anestrus, from the day of weaning to 32 days after weaning (trial I). A linear increase in plasma LH and E was observed in six sows which remained in anestrus (LH, 0.32–0.47 ng/ml; E, 16.1–24.7 pg/ml). These concentrations were similar to those observed in cycling sows during diestrus. In the remaining sows concurrent peaks of LH and E were observed during proestrus and estrus. In a second trial, two groups each of five sows were treated with a single injection of pregnant mare’s serum gonadotropin (PMSG, 1500 IU) or steroids (estradiol-17β, 1 mg plus progesterone, 2 mg) on the day after weaning. The plasma concentrations of LH and E for 10–12 days after weaning were compared with those of five untreated control sows. In the PMSG-treated group, concurrent peaks of LH (4.7 ± 0.5 ng/ml) and E (121 ± 41 pg/ml) were observed at estrus. The control group produced a lower LH peak at estrus (1.5 ± 0.4 ng/ml) which was not accompanied by a rise in plasma E. No consistent secretory pattern for plasma LH and E was observed in the steroid treatment group.

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