PLASMA PROLACTIN LEVELS IN CASTRATED LAMBS WITH AND WITHOUT TESTOSTERONE TREATMENT

in Journal of Endocrinology
Authors:
J. P. RAVAULT
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A. BARTKE
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A. CARATY
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I.N.R.A., Physiologie de la Reproduction, Nouzilly 37380, Monnaie, France

(Received 12 July 1976)

In male lambs born in October, plasma luteinizing hormone (LH) levels increase linearly up to 70 days of age, and plasma testosterone levels continue to increase until 100 days (Cotta, Terqui, Pelletier & Courot, 1975). In contrast, concentration of prolactin in the plasma remains low during the first 10 weeks of postnatal life, then rapidly increases to reach maximum values at approximately 12 weeks and falls to basal levels 1 or 2 weeks later (Ravault & Courot, 1975). Since gonadal steroids can influence prolactin release (Shin, Acken, Roberts & Howitt, 1974; Shaar, Euker, Riegle & Meites, 1975), it is of interest to determine whether this prepubertal peak of plasma prolactin is testis- or testosterone-dependent.

Out of ten Ile de France lambs born in October, eight were castrated 8 days after birth and two were left intact. The

 

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