Plasma Growth Hormone and Prolactin Levels in Healthy Sedentary Young Men after Short-Term Endurance Training under Hot Environment / NIVOI PLAZMINOG HORMONA RASTA I PROKLATINA KOD ZDRAVIH SEDENTARNIH MLADIH LJUDI NAKON KRATKOTRAJNOG TRENINGA U TOPLOM OKRUŽENJU

Abstract

Pituitary hormones play an important role energy expenditure and body temperature regulation during exercise. The aim of the stu¬dy was to investigate the effect of two different endurance training in ambient temperature (30.76 ± 1.71oC and 57.92 ± 5.80% r.h.) on plasma growth hormone (GH) and prolactin (PRL) levels in non-trained healthy subjects. Twenty-four untrained healthy men participated in an 8-wk progressive two different endurance-training program. Subjects were divided into two groups: an in¬ter¬val running group (IR), and continuous running group (CR). Both groups were performed 3 days/wk. Growth hormone, PRL and VO2max levels were assessed at the beginning and the end of the training period. Body temperature (TB) was also measured at the be¬ginning and immediately after each training. The exercise type affected plasma PRL (8.52 vs. 6.50 ng/ml IR and CT groups, P0.38). Plasma GH level at the end of training pro¬gram increased from 0.42 to 1.48 ng/ml and 0.58 to 0.67 ng/ml for IR and CR groups. Expectedly, both training types increased TB, at a greater rate for IR group than CR group. In conclusion, an 8-wk regular exercise result in an increase in plasma PRL level, with¬out altering plasma GH level, which accompanied by elevated body temperature, regardless of the individual’s sporting rou¬ti¬ne. These suggest that untrained individuals could benefit from a regular exercise program as much as those doing the routine sport.

Hipofizini hormini imaju važnu ulogu u potrošnji energije i regulaciji tjelesne temperature tokom vježbanja. Cilj istraživanja bio je da se ispita uticaj dva različita treninga izdržljivosti u sobnoj temperaturi (30.76 ± 1.71oC i 57.92 ± 5.80% r.h.) na nivo plazminog hormona rasta (GH) i proklatina (PRL) kod neobučenih zdravih ispitanika. Dvadesetčetvorica neobučenih zdravih muškaraca učestvovali su u dva različita osmonedjeljna progresivna programa treninga izdržljivosti. Učesnici su bili podijeljeni u dvije grupe: grupu koja je povremeno trčala (IR), i grupu koja je neprestano trčala (CR). Obije grupe su izvodile vježbe 3 dana nedjeljno. Nivo hormona rasta, PRL-a i VO2max procjenjivan je na početku i na kraju perioda treniranja. Tjelesna temperature (TB), takođe je mjerena na početku svakog treninga i odmah nakon istih. Ovaj tip vježbe uticao je na plazmin PRL (8.52 naspram 6.50 ng/ml IR i CT grupe, P < 0.02) ali nije mijenjao nivoe plazminog GH (0.95 naspram 0.63 ng/ml IR i CT grupe, P>0.38). Nivo plazminog GH na kraju programa treniranja povećao se od 0.42 do 1.48 ng/ml i od 0.58 do 0.67 ng/ml za IR i CR grupe. Kao što je očekivano, oba tipa treninga povećala su TB, pri čemu je rast bio veći kod IR grupe nego kod CR grupe. Zaključeno je da je osmonedjeljno redovno vježbanje rezultiralo porastom nivoa plazminog proklatina, ne mijenjajući nivo plazminog hormona rasta, što dalje prati povišena tjelesna temperatura, bez obzira na sportske rutine pojedinca. Ovo nagovještava da neobučeni individualci mogu imati koristi od redovnog programa treniranja u istoj mjeri koliko i oni koji rutinski treniraju.