Seasonal changes in testicular size and in plasma follicle-stimulating hormone and prolactin concentrations in thyroidectomized male and thyroidectomized castrated starlings (Sturnus vulgaris)

1986 ◽  
Vol 63 (1) ◽  
pp. 38-44 ◽  
Author(s):  
A. Dawson ◽  
A.R. Goldsmith ◽  
T.J. Nicholls
Keyword(s):  
Seasonal Changes ◽  
Follicle Stimulating Hormone ◽  
Sturnus Vulgaris ◽  
Testicular Size ◽  
Stimulating Hormone

FEEDBACK CONTROL OF FOLLICLE-STIMULATING HORMONE IN PRE-AND POSTPUBERTAL RAMS AS REVEALED BY HEMICASTRATION

1978 ◽  
Vol 77 (1) ◽  
pp. 75-84 ◽  
Author(s):  
J. S. WALTON ◽  
JANET D. EVINS ◽  
G. M. H. WAITES
Keyword(s):  
Feedback Control ◽  
Seasonal Changes ◽  
Follicle Stimulating Hormone ◽  
Compensatory Hypertrophy ◽  
Expected Time ◽  
A Value ◽  
Selective Increase ◽  
Stimulating Hormone

The levels of FSH, LH and testosterone in the plasma were measured in cross-bred male lambs which were bilaterally castrated, hemicastrated or left entire at 1 week of age. Removal of one testis caused the level of FSH in the circulation to increase to a value midway between the levels found in entire and castrated lambs up to 12 weeks of age. The concentrations of LH and testosterone in the plasma were similar in the control and hemicastrated lambs. The concentration of FSH in the plasma of the hemicastrated lambs fell at 12–14 weeks of age, the expected time of puberty, to the level found in control animals of the same age. Although the possibility of increased release of LH cannot be excluded, the increase in the secretion of FSH is believed to account for the compensatory hypertrophy of the remaining testis observed in the hemicastrated lambs. Removal of one testis from mature Soay rams in spring (May) caused a small selective increase in the concentration of FSH in the plasma, compared with entire animals. This difference was maintained until July when there was a marked increase in the levels of FSH and LH in the hemicastrated rams such that an exaggeration of the normal seasonal changes in these hormones was observed. Compensatory hypertrophy of the remaining testis was observed in the hemicastrated animals.

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