Metabolic and Histological Pancreatic Changes Induced by Orchidectomy in DogsSponsored by the “Consejo Nacional de Investigaciones Cientificas y Tècnicas” (CONICET), Res. Grant no. 2304-h, by Buenos Aires University, by “Alberto J. Roemmers Foundation” and by “Lucio Cherny Foundation”, Argentina. Presented in abstract from at the Meetings of the XXVII International Congress of Physiological Sciences, Paris, July 18-23 (1977).
22. April 2008 (online)
The actions of orchidectomy on the regulation of BS, serum IRI and circulating FFA levels in dogs during glucose-induced hyperglycemia and insulin-induced hypoglycemia were studied. The insulin-secretory potency of these animals was evaluated through measurement of pancreatic insulin content and immunocytolocalization of insulin in the pancreatic islets. Despite orchidectomy performed 4 months in advance, the castrated dogs were neither obese nor hypothyroid by the time of experiments; obesity was observed 10 months after operation.
The pancreatic insulin content in the orchidectomized dogs was normal. Nevertheless, the cytological study indicated their pancreatic insulin secretory potency to be high. Very voluminous, round islets occupied a central position in their pancreatic β-cells, and some vacuolation was observed. Quite a number of round small islets and microislets presenting a great content of secretory granules irregularly scattered in periphery were found; these granules bordered the cell membranes of the vasculary poles of the β-cells which had, therefore, excentric nucleuses.
Orchidectomy failed to affect the basal levels of BS, serum IRI, circulating FFA, the constant rate for insulin clearance from circulation and the BS profile during glucose and insulin tolerance tests. The insulinemic response to hyperglycemia in the orchidectomized dogs was more intense than normal despite their insulin space being two-fold above normal. Orchidectomy promoted fat storage by increasing the uptake of circulating FFA by tissues during hyperglycemia as well as by abolishing the lipolytic response to hypoglycemia.
This study leads us to conclude that orchidectomy induces hyperinsulinism and most presumably also a decrease in the insulin antagonism, which promote fat storage and predispose for late obesity.
Intravenous Glucose Tolerance Test - Insulin Tolerance Test - Blood Sugar - Serum Insulin - Serum Free Fatty Acids - Orchidectomy - Dogs