NON-ESSENTIAL ROLE OF PROLACTIN IN THE HORMONAL RESTORATION OF LACTATION IN GOATS WITH RADIO FREQUENCY HYPOTHALAMIC LESIONS.

Abstract

AbstractGale, C. C. Non‐essential role of prolactin in the hormonal restoration of lactation in goats with radio frequency hypothalamic lesions. Acta physiol. scand. 1963. 59. 269–283.–Coagulation of the median eminence by radio frequency heating in three of four lactating goats caused an abrupt onset of diabetes insipidus and a decline in milk production to 15 to 30 per cent of pre‐lesion levels. One goat with unilateral injury in the median eminence developed diabetes insipidus briefly but showed little block of lactation. In goats with depressed lactation, the administration of ACTH, STH, T3, and insulin restored milk production to, or above, pre‐lesion levels. Since no deficiency in secretion of prolactin could be demonstrated in goats with hypothalamic regulation interrupted by median eminence lesions, these data are in accord with the hypothesis that prolactin secretion is controlled by a central inhibitory mechanism. Diabetes insipidus developing after RF lesions was characterized by an abrupt onset of polyuria and polydipsia, followed by a well‐demarcated normal interphase, and, then, by a permanent phase of elevated water turnover. An amelioration of diabetes insipidus usually paralleled the decline in milk production after lesions, whereas hormonal replacement, particularly with ACTH and T3, restored levels of water turnover above the maximum attained acutely after lesions. Thus, the participation of adenohypophysial hormones is required for the full manifestation of diabetes insipidus in the goat.