In vivo and in vitro Interference of Phosphatidylserine Liposomes on Prolactin Secretion in the Rat

Abstract

The effect of sonicated suspensions of phosphatidylserine (PS), an acidic phospholipid, was investigated on prolactin secretion utilizing in vivo and in vitro approaches. Acute and chronic administration of PS reduced plasma prolactin levels during different phases of circadian rhythms. The phospholipid was able to inhibit the plasma prolactin surge, which occurs in cycling female rats on the afternoon of proestrus. The time course of PS on prolactin secretion was characterized by a short latency (15 min) and a long duration of action (6 h). In rats with hypothalamic deafferentation PS partially reduced the increase of circulating prolactin induced by pre-treatment with α-methyltyrosine. An inhibition of prolactin release was observed if anterior pituitary glands were incubated in presence of PS. This effect was prevented by the addition of the dopamine antagonist sulpiride to the medium. In conclusion, PS decreases prolactin secretion both in vivo and in vitro. The inhibition of the hormone secretion appears to be due to the action of PS at the level of the pituitary; however, a concomitant stimulatory action on the turnover of the tuberoinfundibular neurons cannot be ruled out.

Age-Dependent Changes in the Mechanisms Controlling Prolactin Secretion and Phosphatidylinositol Turnover in Male Rats: Effect of Phosphatidylserine

“…Since DA as well as bromocriptine [7] have been shown to inhibit PI turnover, considered to be one of the earliest postreceptor events controlling PRL secretion at pituitary level [27,33], we investigated the effect of aging on this par ameter.…”

“…BC-PS stimulates the ac tivity of tyrosine hydroxylase in rat brain [34], induces DA release from striatal dopaminergic terminals [23] and stimu lates DA-dependent adenylate cyclase in rat hypothalamus [21]. Furthermore, BC-PS, upon systemic administration, has been shown to reduce plasma PRL levels both in the rat [7] and human [ 16,38). This effect has been described as due to BC-PS interac tion with the dopaminergic hypothalamic system which in turn exhibits its inhibitory role on PRL release [22,37], Re cently, however, an action of BC-PS on pituitary PI turn over has been reported [4], suggesting that the hypoprolactinemizing effect of this phospholipid may also be related to a direct effect on pituitary mammotrophes.…”

The Potential Role of Hypothalamic Phospholipid Liposomes in the Supportive Therapy of Some Manifestations of Post-COVID-19 Condition: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Brain Fog

“…On the other hand, there is extensive preclinical and clinical evidence that hypothalamic phospholipid liposomes increase monoaminergic neurotransmission, as shown by the activation of tyrosine hydroxylase (the rate-limiting enzyme in the synthetic pathway of dopamine and other catecholamines); the increase in monoamines turnover and release; the stimulation of the dopamine-dependent adenylyl cyclase and the increase in dopamine metabolite levels in human cerebrospinal fluid (CSF); the decrease in prolactin secretion through dopamine agonist activity (dopamine being the main inhibitor of the prolactin synthesis and release); and, finally, the modification of the receptor adaptation of central aminergic neurons to chronic treatment with antidepressants [47,48,[58][59][60][61]. The monoaminergic effect of hypothalamic phospholipid liposomes renders them highly relevant for the treatment of fatigue, where a dopaminergic effect is particularly needed, as well as for the treatment of other COVID-19 neuropsychiatric sequalae, such as anxiety and depression.…”