Effect of ACTH on lipolysis in adipose tissue of normal and adrenalectomized rats in vivo

Abstract

Parametrial fat-pads of fed rats were perfused in vivo. Rates of release of glycerol and free fatty acids (FFA) were determined from venous-arterial difference and plasma flow. Adrenalectomy lowered basal release of FFA and glycerol, but not reesterification of FFA within the fat-pad. ACTH (5 mug iv) in normal rats increased release of FFA and glycerol (mumol-g-1-h-1) from basal values of 0.90 and 0.48 to 3.2 and 1.3, respectively, and in adrenalectomized rats from 0.41 and 0.33 to 1.5 and 3.1, respectively. Thus in normal rats ACTH increased the molar ratio of FFA to glycerol released from 1.9 to 2.5, whereas in adrenalectomized rats the ratio fell from 1.3 to 0.5. After stimulation of lipolysis in normal rats 85% of the FFA formed were released but only 20% in adrenalectomized rats; the remainder was reesterified to triglyceride. It is concluded that adipose tissue of adrenalectomized rats is sensitive to the lipolytic activity of ACTH, but increased glucose utilization by adipocytes in the absence of glucocorticoid enhances reesterification and reduces release of FFA by the tissue.

Reintoxication: the release of fat‐stored Δ9‐tetrahydrocannabinol (THC) into blood is enhanced by food deprivation or ACTH exposure

“…This presumably occurred due to ACTH-induced lipolysis in vivo. Previous studies, as well as the current one, have shown that systemic administration of ACTH increases lipolysis, as gauged by increased plasma levels of glycerol ( Spirovski et al, 1975;Opmeer et al, 1978;Boston and Cone, 1996).…”

Food-intake regulation during stress by the hypothalamo-pituitary-adrenal axis

“…Indeed, MC-2 receptors are expressed in white and brown adipocytes both at the mRNA and protein levels (Iwen et al, 2008) and ACTH stimulates free fatty acid release from epigastric adipose tissue of rabbits (Lewis and Matthews, 1968). Thus, ACTH has a direct lipolytic activity -present also in ADX rats -however, this effect is substantially lower than that of GCs (Spirovski et al, 1975). Insulin-induced glucose uptake in white adipocytes is reduced by ACTH treatment, thereby here not only the indirect (through GCs), but also the direct effect of ACTH is antagonistic to insulin.…”

The Vasopressin-Deficient Brattleboro Rat: Lessons for the Hypothalamo–Pituitary–Adrenal Axis Regulation

“…Similar to glucocorticoids, ACTH has also a direct anti-inflammatory action both on the thymus and the circulating lymphocytes (Brod and Hood 2011;Catania et al 2011;Montero-Melendez et al 2011). Its effect on the metabolism includes direct brain, liver, pancreas, and brown adipose tissue effects, resulting in regulation of carbohydrate and lipid homeostasis (Lesault et al 1991;Lewis and Matthews 1968;Spirovski et al 1975) as well as thermoregulation and food intake (Schulz et al 2009). …”