High postheparin lipolytic activity as a possible cause of hypotriglyceridemia in spontaneously hypertensive rats.

In male spontaneously hypertensive rats (SHR) and normotensive Wistar rats at 4, 8 and 20 weeks of age the postheparin lipolytic activity (PHLA) has been estimated. PHLA was significantly higher in all SHR than in age- and weight-matched controls, although it decreased with advancing age in both groups. The data are discussed with regard to hyperinsulinemia and hypotriglyceridemia in SHR ascertained by a previous study. It is assumed that in young SHR catecholamine-induced lipolysis provokes impaired glucose tolerance and higher insulin response after glucose load. Insulin enhancement can stimulate PHLA via increased synthesis of lipoprotein lipase. The resulting augmented uptake of triglycerides by adipose tissue is suggested to be a beneficial (adaptive?) mechanism to compensate a primary increase of lipolysis. The well-known lower adipose cell size and body weight in SHR in comparison to age-related normotensive control rats might indicate that this mechanism is insufficient to balance the triglyceride supply in these animals.